Multi-blade, high volume low speed (HVLS) cooling fans are often used in warehouses, commercial buildings, loading docks, and other large structures to provide a comfortable work environment and/or to maintain suitable temperatures for product storage. Such fans are typically hung from the ceiling, and can include a plurality of blades extending outwardly from a central, motor-driven hub. In operation, HVLS fans rotate at relatively low speeds to produce a large downdraft of slowly moving air.
Conventional ceiling fan blades are generally flat and have constant cross-sections from root to tip. Others can include upwardly-angled airfoil extensions or winglets on the tips, or flat plates that simply cap off the tips as taught in, for example, U.S. Pat. Nos. 7,252,478, 7,284,960, 7,654,798, 8,162,613, and 8,821,126. While these tip devices may reduce aerodynamic drag, they also increase the weight of the blades at their outer ends. The increased weight at the blade ends can increase the rotational inertia of the fan and have a negative effect on performance, which can also lead to increased power consumption. Accordingly, reducing the weight of blade tip devices is desirable.